The high-dose estrogen group was discontinued in 1970 due to increased non-fatal cardiovascular complications and an unfavorable trend in overall mortality, while the low-dose estrogen group was discontinued in 1970 due to lack of indication of benefit and also an unfavorable trend in overall mortality.[1][2][4][5][6] Both dose levels of estrogen as well as clofibrate were also found to increase the incidence of gallbladder disease in the study.[7] The dextrothyroxine group was discontinued in late 1971 due to increased cardiovascular mortality.[1][8]
The Coronary Drug Project Aspirin Study was a substudy of the CDP which randomized men from the estrogen and dextrothyroxine groups of the trial which had been terminated early to either aspirin or placebo.[9][10][5]
^"The Coronary Drug Project. Findings leading to discontinuation of the 2.5-mg day estrogen group. The coronary Drug Project Research Group". JAMA. 226 (6): 652–7. November 1973. doi:10.1001/jama.1973.03230060030009. PMID4356847.
^Stamler J (1977). "The Coronary Drug Project --- Findings with Regard to Estrogen, Dextrothyroxine, Clofibrate and Niacin". Atherosclerosis. Advances in Experimental Medicine and Biology. Vol. 82. pp. 52–75. doi:10.1007/978-1-4613-4220-5_6. ISBN978-1-4613-4222-9. PMID335823.
^Coronary Drug Project Research Group (May 1977). "Gallbladder disease as a side effect of drugs influencing lipid metabolism. Experience in the Coronary Drug Project". N Engl J Med. 296 (21): 1185–90. doi:10.1056/NEJM197705262962101. PMID323705.
^"The coronary drug project. Findings leading to further modifications of its protocol with respect to dextrothyroxine. The coronary drug project research group". JAMA. 220 (7): 996–1008. May 1972. doi:10.1001/jama.1972.03200070084015. PMID4337170.
^"The coronary drug project aspirin study. Implications for clinical care. Coronary Drug Project Research Group". Prim Care. 5 (1): 91–5. March 1978. doi:10.1016/S0095-4543(21)00774-0. PMID349581.
^"Aspirin in coronary heart disease. The Coronary Drug Project Research Group". Circulation. 62 (6 Pt 2): V59–62. December 1980. PMID7002353.